1. Field
The present invention relates to mobile communication systems.
2. Background
Advances in technology have resulted in smaller and more powerful computing devices. For example, there currently exist a variety of portable personal computing devices, including wireless computing devices, such as portable wireless telephones, personal digital assistants (PDAs), and paging devices that are small, lightweight, and easily carried by users. More specifically, portable wireless telephones, such as cellular telephones and Internet Protocol (IP) telephones, can communicate voice and data packets over wireless networks. Many such wireless telephones incorporate additional devices to provide enhanced functionality for end users. For example, a wireless telephone can also include a digital still camera, a digital video camera, a digital recorder, and an audio file player. Also, such wireless telephones can execute software applications, such as a web browser application that can be used to access the Internet. As such, these wireless telephones can include significant computing capabilities.
Some wireless telephones may include multiple subscription capability. For example, each subscription may be associated with a different wireless telephone number. When a wireless telephone includes multi-subscription capability, the wireless telephone may occasionally tuneaway from a primary network to listen for data on one or more secondary networks. During tuneaway from a first network to a second network, the wireless telephone may go out-of-sync with the first network. Messages transmitted or retransmitted by the first network to the wireless telephone during the tuneaway period may not be received by the wireless telephone.